X is an element in the form of a powder. X burns in oxygen and the product is soluble in water. The solution is tested with litmus. Write down only the word, which will correctly complete the following sentence.
If X is a metal it will form ____ oxide, which will form ____ solution with water.

Explanation

To solve the problem, we need to analyze the information given in the question and apply our understanding of metals and their oxides.

### Step-by-Step Solution:

1. **Identify the Element**: We are given that X is an element in the form of a powder that burns in oxygen. This indicates that X is likely a metal since metals typically react with oxygen.

2. **Determine the Product**: When X burns in oxygen, it forms an oxide. The problem states that this oxide is soluble in water.

...